ROSE ON THE ANHYDROUS SULPHATE OF AMMONIA. 555 



paper; in both these cases the solutions instantly precipitate 

 the salts of barytes and lead. 



If hydrochloric acid and a solution of chloride of barium be 

 added to one of parasulphat-ammon, it remains also for some 

 time perfectly clear ; in about twelve hours, however, a precipi- 

 tate of sulphate of barytes is formed; but it does not occur 

 without the hydrochloric acid be present. 



In the property of not precipitating the solutions of barytic 

 salts in the cold, the parasulphat-ammon very much resembles 

 the compound obtained by M. Regnault, by saturating sulphate 



of chloride of sulphur S CF + 2 S (S CI) with anhydrous am- 

 monia*, and which he considered as a mixture of sal-ammoniac 



and a sulfamide (S N H^). The solution of this compound oc- 

 casions no precipitation with the salts of barytes, even when 

 they have been long in contact. M. Regnault did not succeed 

 in separating this sulfamide from sal-ammoniac by crystalliza- 

 tion ; and he adds, moreover, that the compound which he ob- 

 tained very soon attracts moisture from the air, which, as already 

 mentioned, is not the case with the crystals of parasulphat-am- 

 mon or suljjhat-ammon. 



The results of analyses prove, likewise, that the crystals can- 

 not be regarded as an anhydrous sulfamide; 100 parts dissolved 

 in water, were mixed w ith a solution of the chloride of barium 

 and boiled. After some time a precipitate of sulphate of ba- 

 Tytes appeai-ed, but less in quantity and inuch more slowly than 

 would have occurred, under similar cii'cumstances, w ith a solu- 

 tion of sulphat-ammon. The whole was evaporated to diy- 

 ness ; the residue heated to incipient redness, left 203"64 parts 

 of sulphate of barytes after treatment with hydrochloric acid 

 and water ; this is equivalent to 70 of sulphuric acid. 



The result of this analysis proves that these crystals possess 

 as exactly as possible the same composition as the anhydrous 

 sulphate of ammonia or sulphat-ammon. If the sulphur in an 



anhydrous sulfamide S N H- was entirely converted into sul- 

 phuric acid, there would be obtained 80"03 per cent, of sul- 

 phuric acid from the sulfamide employed. 



One hundred parts of crystals of parasulphat-ammon, which 

 had been formerly prepared, gave, when treated in the same 



* .inn. dc ('him. et de Phys. Ixix., 170. 



